Changes in weight and free fatty acid concentration of fat bodies of paedogenic Ambystoma tigrinum during vitellogenesis

Abstract

1. 1. A direct correlation was found between the rate of fat body depletion and ovarian development in paedogenic Ambystoma tigrinum. 2. 2. Out of ninety animals examined only a few were observed in intermediate stages of gonadal development. This indicates that once vitellogenesis begins it proceeds at a rapid rate. 3. 3. Potentiometric titrations of fat body lipids revealed that the free fatty acid concentration increased markedly as the fat bodies were depleted. 4. 4. Equivalent chain length analyses of the total fatty acid composition of the fat bodies revealed the presence of lauric, myristic, plamitic, palmitoleic, steric, oleic, linoleic and arachidic acids. There was no apparent change in their relative concentrations at different stages of vitellogenesis. 5. 5. These findings suggest that the free fatty acids in the fat bodies may be involved in the regulation of oxidative metabolism for cell synthesis as opposed to reductive metabolism and synthesis of storage materials in the later stages of egg development.